Surprise Democrat Defection Helps Markwayne Mullin’s DHS Secretary Nomination Advance

Indian Affairs Committee Hearings to examine Indian Self-Determination and Education Assistance Act successes and opportunities at the Department of the Interior and the Indian Health Service, in Washington, DC on September 17, 2025. (Official U.S. Senate photo by Ryan Donnell)

The Senate on Sunday advanced President Donald Trump’s nomination of Republican Oklahoma Sen. Markwayne Mullin to serve as the next Secretary of the Department of Homeland Security, aided by unexpected support from a Democratic lawmaker.

In a rare Sunday session, senators voted 54–37 to invoke cloture on Mullin’s nomination, setting up a final confirmation vote expected early in the week, according to The Hill. While Democratic Sen. John Fetterman of Pennsylvania had already signaled his support, New Mexico Sen. Martin Heinrich’s vote to advance the nomination came as a surprise.

Heinrich explained his decision in a statement, emphasizing his working relationship with Mullin:

“This is going to surprise some people, but I consider Markwayne Mullin a friend. We have a very honest and constructive working relationship,” Heinrich, a third-term member of the upper congressional chamber, wrote in a statement justifying the vote. “We have authored legislation together, such as the Tribal Buffalo Management Act, and we crafted the Legislative Branch Appropriations bill together this year. We often disagree and when we do, we work to find whatever common ground we share.”

“I have also seen first-hand that Markwayne is not someone who can simply be bullied into changing his views, and I look forward to having a Secretary who doesn’t take their orders from Stephen Miller,” the New Mexico Democrat added, naming the White House deputy chief of staff long known for his hardline stance on immigration.

“For five years, under this and the previous Trump Administration, I have lacked any constructive relationship with the Secretary of Homeland Security. This is despite my state being home to hundreds of TSA [Transportation Security Administration], CBP [Customs and Border Protection] and Border Patrol constituents and many miles of the U.S./Mexico border,” Heinrich continued, naming three agencies of the DHS.

“I want someone who recognizes the necessity of judicial warrants, as he has. I would like a Secretary who I can call and have a constructive conversation with about my state and the unique terrain that exists in the southwest and the proper mix of structure, technology and personnel necessary to effectively secure our border,” the Democrat went on to say. “For these reasons, I will vote to confirm Markwayne Mullin to be Secretary of Homeland Security.”

Fetterman, who sits on the Senate Homeland Security Committee, had already voted to advance Mullin’s nomination out of committee last week as part of an 8–7 majority.

He also publicly backed Mullin when the nomination was first announced, writing on March 5 that he would support his Senate colleague for the role.

Despite broad Republican support, Kentucky Sen. Rand Paul—chair of the Homeland Security Committee—broke with his party and opposed advancing the nomination both in committee and on the Senate floor.